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Iodine, Seaweed and the Thyroid: A Safety Guide for Prostadine Buyers
The thyroid uses iodine to make hormones; adults need 150 mcg a day and the upper limit is 1,100 mcg. Prostadine lists four seaweeds plus iodine itself with no amounts printed, so the total is unknown. The American Thyroid Association advises against supplements over 500 mcg. Ask a doctor first with any thyroid condition.
Written by the Prostadine label deskUpdated
Why it matters01
What the thyroid does with iodine
The thyroid, a small gland at the front of the neck, takes iodine from the blood and builds it into thyroid hormones. Those hormones help set how fast the body uses energy, and they matter for heart rate, temperature, weight and mood.
Because the body cannot make iodine, it has to come from food. The American Thyroid Association lists iodized salt, dairy, eggs, saltwater fish and shellfish, and notes kelp, kombu, nori and dulse as dietary sources. Too little can cause a goiter, an enlarged thyroid, and an underactive thyroid (ATA, Iodine deficiency).
Prostadine's bottle front carries a small tile that reads 53, I, Iodine, and the info page lists nori, wakame, kelp and bladderwrack, which are seaweeds, and iodine on its own. That combination makes this the most important safety topic on the site.
The numbers02
Need, advice and ceiling
Daily iodine, micrograms
Four of the nine lines are seaweeds and one is iodine itself, and seaweed iodine varies from 16 to 2,984 mcg per gram (NIH ODS, Iodine). The ATA advises against iodine or kelp supplements above 500 mcg a day (ATA, Excess iodine). The bar for Prostadine is hatched because no amount is printed.
Adults need 150 micrograms a day. The tolerable upper intake is 1,100 micrograms (NIH ODS, Iodine). The ATA says intake above 1,100 is not recommended, that many iodine, potassium iodide and kelp supplements contain amounts far above that limit, by up to several thousand times, and that it advises against supplements providing more than 500 micrograms a day (ATA, Excess iodine).
Too much03
What excess iodine can do
Surprisingly, too much iodine can produce both an underactive and an overactive thyroid. The NIH lists goiter, raised thyroid-stimulating hormone (TSH), hypothyroidism, iodine-induced hyperthyroidism and thyroiditis as outcomes of high intakes (NIH ODS, Iodine).
| If hormone is too low (underactive) | If hormone is too high (overactive) |
|---|---|
| Tiredness, feeling cold, weight gain | Racing or irregular heartbeat, feeling hot, weight loss |
| Dry skin, constipation, low mood | Nervousness, tremor, trouble sleeping |
| A swelling at the front of the neck | A swelling at the front of the neck |
None of those signs is specific, and each has many other causes. The reliable step is a blood test, which a doctor can order. If you notice such changes after starting a seaweed or iodine product, stop it and tell your doctor, and keep the bottle to show them.
Antithyroid drugs plus extra iodine can add up to hypothyroidism (NIH ODS, Iodine). Never stop or change thyroid medicine without the prescriber's advice.
Everyday iodine04
Food and supplements add to the same daily total
Iodine arrives from several directions at once, and the body does not care which. A reader trying to stay inside the limits has to think about the whole day, not only the bottle.
| Source | What is known | Source |
|---|---|---|
| Iodized salt, dairy, eggs, saltwater fish, shellfish | Listed as common dietary sources | ATA (ATA, Iodine deficiency) |
| Dried nori, 5 g | About 116 mcg, close to three quarters of the 150 mcg daily need | NIH ODS (NIH ODS, Iodine) |
| Kelp, kombu, dulse and other seaweeds | 16 to 2,984 mcg per gram; highly variable | NIH ODS (NIH ODS, Iodine) |
| Kelp and iodine supplements | Some hold up to several thousand times the upper limit | ATA (ATA, Excess iodine) |
| A multivitamin | Often lists iodine; check the panel | Check your own label |
| Prostadine, one 2 mL serving | Not printed; four seaweeds plus iodine itself | Info page |
The takeaway is practical. If you already eat seaweed often, use a kelp tablet or take a multivitamin with iodine, tell your pharmacist before adding drops that carry five iodine sources, and consider keeping the tally in a notebook for a week.
Prostadine: from $49 a bottle60 mL · 2 mL a day · free US shipping on 3 or 6 · 60-day money-back guarantee
See packsWho is more vulnerable05
People for whom iodine needs extra care
The ATA names older adults, pregnant and breastfeeding women, infants and people with existing thyroid disease as more vulnerable to excess iodine (ATA, Excess iodine). The NIH adds two medicine interactions: antithyroid drugs, and potassium iodide with ACE inhibitors or potassium-sparing diuretics, which can raise potassium (NIH ODS, Iodine).
Many men considering a prostate supplement are in or near the older-adult group, and many take blood pressure medicines. That overlap is why an ordinary-looking supplement deserves a pharmacist's glance. The medicines page sets the combinations out.
Your doctor06
Five questions to ask about iodine
Do I have a thyroid condition or a risk of one?
A family history, a past test or a goiter all count. Say so.
Should I have a thyroid blood test before and after?
A baseline test gives a comparison if symptoms appear. Ask whether it suits you.
Does my medicine interact with iodine?
Bring the list, including antithyroid drugs, ACE inhibitors and diuretics (NIH ODS, Iodine).
How much iodine do I already get?
Salt, dairy, eggs, fish and a multivitamin all add to the total.
Is a seaweed supplement sensible for me?
Ask for a straight answer for your history, and show the bottle.
Take the label with you. The seller can supply the iodine per serving in writing, and the label page explains how to ask.
- Iodine: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2024.RDA for adults is 150 mcg a day; the tolerable upper intake level is 1,100 mcg a day. Dried nori, 2 tablespoons of flakes (5 g): 116 mcg. Seaweeds range from 16 to 2,984 mcg per gram. High intakes can cause goiter, elevated TSH and hypothyroidism, and iodine-induced hyperthyroidism and thyroiditis. Interactions: antithyroid drugs (additive effect, hypothyroidism), and potassium iodide with ACE inhibitors or potassium-sparing diuretics (hyperkalemia risk).
- ATA Statement on the Potential Risks of Excess Iodine Ingestion and Exposure. American Thyroid Association, 2024.Iodine is needed for normal thyroid function (150 mcg a day for adults). Intake above 1,100 mcg a day is not recommended. Many iodine, potassium iodide and kelp supplements contain amounts far above the upper limit, by up to several thousand times. The ATA advises against taking iodine or kelp supplements that provide more than 500 mcg of iodine a day. Older adults, pregnant and breastfeeding women, infants and people with existing thyroid disease are more vulnerable.
- What Is Iodine Deficiency?. American Thyroid Association, 2024.The body cannot make iodine; it comes from food. Iodized salt, dairy, eggs, saltwater fish and shellfish are listed sources, and kelp, kombu, nori and dulse are listed as dietary sources. Deficiency can cause goiter and hypothyroidism. The page does not discuss excess iodine or seaweed supplements.
FAQ07
Prostadine questions people ask
Can too much iodine harm the thyroid?
Yes. High intakes can cause goiter, an underactive thyroid, an overactive thyroid and thyroiditis (NIH ODS, Iodine). The upper limit for adults is 1,100 mcg a day.
How much iodine do I need every day?
Adults need 150 mcg a day, and more in pregnancy and breastfeeding. Most people in countries with iodized salt get enough, and the American Thyroid Association lists common food sources (ATA, Iodine deficiency).
Is seaweed iodine the same as iodine in salt?
Both are iodine, but seaweed content swings widely, from 16 to 2,984 mcg per gram (NIH ODS, Iodine), while iodized salt is standardised. That variability is the problem with seaweed supplements.
Should I stop Prostadine if I get thyroid symptoms?
Stop the drops and tell your doctor, who can test your thyroid. Do not change prescribed medicine without advice, and bring the bottle with you.
Who wrote this08
Written and reviewed by
Pages built from the bottle photos, the info page and linked NIH, FDA, NCI, FTC and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a licensed U.S. retail desk for Prostadine, not by the manufacturer. We earn money when you buy through our order links.
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